Protection of Hidden Vol.
Data in RAM
to Back Up
MCrypt is a software system for establishing and maintaining an
on-the-fly-encrypted volume (data storage device). On-the-fly encryption means
that data is automatically encrypted or decrypted right before it is loaded or
saved, without any user intervention. No data stored on an encrypted volume can
be read (decrypted) without using the correct password/keyfile(s) or correct
encryption keys. Entire file system is encrypted (e.g., file names, folder
names, contents of every file, free space, meta data, etc).
Files can be copied to and from a mounted MCrypt volume just like they are
copied to/from any normal disk (for example, by simple drag-and-drop
operations). Files are automatically being decrypted on-the-fly (in memory/RAM)
while they are being read or copied from an encrypted MCrypt volume.
Similarly, files that are being written or copied to the MCrypt volume are
automatically being encrypted on-the-fly (right before they are written to the
disk) in RAM. Note that this does not
mean that the whole file that is to be
encrypted/decrypted must be stored in RAM before it can be encrypted/decrypted.
There are no extra memory (RAM) requirements for MCrypt. For an illustration
of how this is accomplished, see the following paragraph.Let's suppose
that there is an .avi video file stored on a MCrypt volume (therefore, the
video file is entirely encrypted). The user provides the correct password
(and/or keyfile) and mounts (opens) the MCrypt volume. When the user double
clicks the icon of the video file, the operating system launches the application
associated with the file type – typically a media player. The media player then
begins loading a small initial portion of the video file from the
MCrypt-encrypted volume to RAM (memory) in order to play it. While the
portion is being loaded, MCrypt is automatically decrypting it (in RAM). The
decrypted portion of the video (stored in RAM) is then played by the media
player. While this portion is being played, the media player begins loading next
small portion of the video file from the MCrypt-encrypted volume to RAM
(memory) and the process repeats. This process is called on-the-fly
encryption/decryption and it works for all file types, not only for video files.
For a quick start guide, please see the chapter Beginner's
Remark: Please note that although most chapters of this
documentation apply generally to all versions of MCrypt, some sections are
primarily aimed at users of the Windows versions of MCrypt. Hence, such sections may contain
information that is inappropriate in regards to the Mac OS X and Linux versions